Temptation: Immediacy and Certainty

Last registered on September 10, 2021


Trial Information

General Information

Temptation: Immediacy and Certainty
Initial registration date
September 12, 2019

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
September 16, 2019, 2:03 PM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Last updated
September 10, 2021, 1:38 AM EDT

Last updated is the most recent time when changes to the trial's registration were published.



Primary Investigator


Other Primary Investigator(s)

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Is an option is especially tempting when it is both immediate and certain? To study the effect of risk on present bias, I conduct an online experiment in which workers allocate about thirty minutes of real-effort tasks between two weeks. I compare choices made two days before the first workday against choices made when work is imminent. In baseline treatments, one choice is randomly implemented; meanwhile, one treatment implements a particular allocation with certainty. By assuming that effort costs are not affected by the mechanism (and thus independent of risk preferences), my novel design permits estimation of present bias using a decision with a consequence both immediate and certain. I find the average intensity of present bias is far greater under certainty than under risk. I find no evidence that present bias is more pervasive among individuals, suggesting instead that present-biased individuals become more myopic.
External Link(s)

Registration Citation

Reddinger, Lucas. 2021. "Temptation: Immediacy and Certainty." AEA RCT Registry. September 10. https://doi.org/10.1257/rct.4651
Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Primary outcomes of interest are the real-effort task allocations chosen by subjects between two weeks.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
The intake questionnaire includes a short demographic survey; these data will be used to predict attrition and may also be used as controls in prediction of primary results.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Subjects must complete an intake questionnaire that tests comprehension of the experimental instructions; subjects must answer all questions correctly to be enrolled in the trial.

On Day 1 (e.g., Monday of Week 1), subjects are asked to allocate approximately 30 minutes of work between Day 2 (e.g., Wednesday of Week 1) and Day 3 (e.g., Wednesday of Week 2). On Day 2, subjects are again asked to allocate work between Day 2 and Day 3. For each subject, an independent fair coin toss determines whether decisions from Day 1 or Day 2 are implemented.

If a subject is assigned to the “Uncertain-Day” treatment, she learns the result of this coin toss after her decisions on Day 2. If a subject is assigned to the “Certain-Day” treatment, she learns the result of this coin toss before her decisions on Day 2.

On each day that decisions are made, subjects are asked to allocate a fixed present value budget of real-effort tasks between Days 2 and 3.
Subjects make allocation decisions for each of five gross interest rates R ∈ {0.5, 0.75, 1, 1.25, 1.5}.

If a subject is assigned to the “Uncertain-List” treatment, after she makes all of her decisions, one of her decisions from the selected day is chosen at random with uniform probability to be implemented. If a subject is assigned to the “Certain-List” treatment, her decision from the selected day for the gross interest rate R = 1.25 is chosen with certainty to be implemented.

Each subject is assigned to a “Day” treatment and a “List” treatment, resulting in a two-by-two factorial design. Each subject is fully informed of the procedures and mechanisms used in her assigned treatment.
Experimental Design Details
Randomization Method
Subjects are enrolled in the order in which they complete the intake questionnaire. Treatments are assigned to subjects using a round-robin algorithm as subjects are enrolled. Randomization of gross interest rates is done in advance using a computer program (using unique seeds to permit replication).
Randomization Unit
Subjects are individually assigned to one of the four treatments.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
The trial will have 192 to 208 subjects; each subject represents a cluster.
Sample size: planned number of observations
Each subject makes 20 allocation decisions. The trial will thus yield 3840 to 4160 observations.
Sample size (or number of clusters) by treatment arms
Certain-Day-Certain-List: 64 subjects.
Certain-Day-Uncertain-List: 64 subjects.
Uncertain-Day-Certain-List: 32 subjects.
Uncertain-Day-Uncertain-List: 32 subjects.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
UCSB, Office of Research, Human Subjects Committee
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Intervention Completion Date
November 06, 2019, 12:00 +00:00
Data Collection Complete
Data Collection Completion Date
November 06, 2019, 12:00 +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
Was attrition correlated with treatment status?
Final Sample Size: Total Number of Observations
Final Sample Size (or Number of Clusters) by Treatment Arms
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials